


Lumina

by ginger_mosaic



Series: The Guinea Pig 'Verse [1]
Category: Supernatural
Genre: #worthit, Alternate Universe - Canon Divergence, Fallen Angel Castiel (Supernatural), Falling Castiel, M/M, Men of Letters Bunker, Post-Season/Series 10
Language: English
Status: Completed
Published: 2017-04-18
Updated: 2017-04-18
Packaged: 2018-10-20 11:08:49
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,877
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10661331
Author URL: https://archiveofourown.org/users/ginger_mosaic/pseuds/ginger_mosaic
Summary: It’s not an easy choice, but it’s one he wants to make.





	Lumina

**Author's Note:**

> This is so friggin’ sappy. Please, somebody stop me.
> 
> This can actually be read as a standalone AU, though it’s the first chronological part of the Guinea Pig ‘Verse series.

_Eve had to ask, Eve had to ask,_

_“What is wrong with this?_

_Here is the place, now is the time—_

_Let's invent the kiss.”_

_Lumina, come and wrap around me._

_Lumina, come and wrap around me._

 

_(Lumina_ , Joan Osborne)

 

* * *

 

 

_Castiel._

He hears the call, but he doesn’t move. Not yet. If he moves now, Dean will wake, and Castiel must wait until he falls into a deep enough sleep that he won’t stir when Castiel pulls away.

That’s only one reason he doesn’t want to leave yet, however. He doesn’t know what’s going to happen, and selfishly, he wants to enjoy this for as long as he can.

_Castiel_.

He traces the features of Dean’s face with his fingertips—the lines of his brow, his cheekbones, his nose. The stubble on his jaw is rough against Castiel’s fingers, but his lips are soft. He runs his thumb along Dean’s bottom lip, and Dean’s mouth falls open slightly and his warm breath ghosts over Castiel’s skin. He wants to kiss him. He wants to wake him so he can look into his green eyes and hold onto the glow of his soul. He wants to stay here and count Dean’s freckles every night for the rest of eternity.

He _wants_ so badly.

_Castiel_.

Carefully, Castiel leans forward and places a kiss on Dean’s forehead. “I will return to you,” he promises quietly, and then he slips out of bed and leaves.

 

* * *

 

It’s a cold morning. He knows this intellectually, at least. The sun has not yet broken over the horizon, only just dyeing the edge of the sky a gentle pink. The day will surely be hot and miserable, as all the other days in this particular Kansas summer have been, but Castiel tries not to think about that. He doesn’t feel it now; only Dean’s complaints tell him how uncomfortable the temperature is. He remembers a lot of the discomfort of being human. He tries not to think about that either.

Hannah stands next to a black sedan in front of the bunker in her male vessel. Castiel closes the bunker door behind himself and steps out to meet her.

“Castiel,” she says in greeting.

“I apologize for keeping you waiting,” he says. “I needed to…” But he doesn’t know how to explain what he needed to do, and why, or how to even start.

When he’s silent for a while, Hannah speaks. “When you called to me, you said you needed my help,” she says. “Are you all right?”

“I—Yes, but—” He cuts himself off and looks away. He thought about this for so long, and now he doesn’t know what to say. How to explain to Hannah, his sister. What he wants. That he wants at all.

It’s been a month. A month since Dean and Sam returned to the abandoned distillery where he and Charlie waited with Crowley and Rowena to find out if the spell from the Book of the Damned worked. Crowley and Rowena had almost come to blows when the Winchesters arrived.

When Dean walked through the door, Castiel nearly fell to his knees. The Mark’s evil had obscured Dean’s soul, and now that darkness was _gone_. His soul—that bright light that even Hell couldn’t smother completely (except, oh God, when the Mark had corrupted it, twisted it into something sick and deformed, and Castiel hadn’t been able to stand it, had made Sam complete the ritual alone)—Castiel could see his soul again. Oh Lord, wherever He was, Castiel could see it again.

Even the news that the spell released the Darkness when it removed the Mark of Cain, that Death had sealed it away temporarily, and that if they didn’t figure out what to do with it soon, it would surely escape—even all the bad news wasn’t enough to overwhelm Castiel’s elation at this one good thing:

_Dean Winchester is saved_.

Crowley and Rowena stopped bickering with each other long enough to become enraged that Dean and Sam denied them access to this unknown powerful force, but Castiel couldn’t take his eyes off Dean and his shining soul long enough to care about their anger or to be irritated with their motivations.

Finally, Charlie cut in. “You know what?” she said, trying for cheerful and only managing an irritated grimace. “I think we’re all beat from this spell and we can continue this discussion later. Also, you know,” she added, lifting her broken arm slightly, “if I don’t get some more painkillers soon, I’m going to kill you all with my brain.”

“Fine,” said Rowena, “but just to be sure you’ll actually call for future discussions—” And with that, she swept up the Book of the Damned and vanished in a whirl of smoke.

Crowley’s parting went similarly. He griped briefly, looked at Dean with something like regret, and disappeared. Dean drove them all back to the bunker, and only there did the levee finally seem to break.

It started with Charlie.

“Well, that was, uh,” Dean began, breaking the silence with an attempt at levity, but Charlie cut him off by bursting into tears and throwing her good arm around him. He stood there, stunned, and it took a few minutes to peel her off him, and even then she appeared unable to form words.

Sam just gave Dean a teary-eyed smile and then escorted Charlie to the room she had been slowly making her own.

Thus leaving Dean alone in the war room with Castiel. It still smelled of gasoline and blood, even though Castiel and Sam had disposed of the Steins’ bodies and cleaned up the pile of Dean’s soaked belongings. They had done it silently, united in their shared grief. Less than seventy-two hours ago, he and Dean had struggled here. Less than seventy-two hours ago, Castiel had lost Dean here.

“Cas,” Dean had said hoarsely, and when Castiel looked up, Dean was staring past him into the library. Dean swallowed heavily and licked his lips and still wouldn’t look at him. He hadn’t looked at him at all, not even in the distillery, since—since—

“I’m sorry,” said Dean at last.

“For what?” asked Castiel when he said nothing more. He bristled then, because there _was_ something Dean _should_ apologize for, but Dean always apologized for the wrong thing, not realizing the _real_ problem. So he spelled it out for him. “For attempting to kill yourself by going to Death and bribing him with—what—nachos?”

Dean looked stricken. “Cas—”

“We were trying to save you, Dean, and you—First you asked me to take you out, and how _could_ you? I can’t—I could never—So instead you called upon _Death_. How—Dean Winchester, you are—”

“I couldn’t stop, Cas,” said Dean, his voice cracking, finally meeting Castiel’s eyes, pleading with him. “I couldn’t stop. And you—” He took a shuddering breath. “Back then. When I—When I met Cain. He had a wife, Colette, and she asked him to stop, and until we came in and dragged him out of retirement, he did. She asked him to stop, and he did. But I—You asked me to stop, and I—”

Castiel stared at him. What was he saying? That Castiel could have stopped him? He bristled with anger again. No. Never. He could never kill Dean, he’d _told_ him that—

But wait. Colette hadn’t stopped Cain. She _asked_ him to stop. Colette had—

And Castiel—

“I was gone, Cas,” Dean whispered, shaking his head. “I was so far gone. And if even you couldn’t—”

Castiel took a step forward.

“If I couldn’t stop even when you—”

And he closed the distance between them then so quickly that he must have flown, in spite of everything, and he grabbed Dean by his jacket and kissed him.

Castiel was inexperienced, had only ever kissed Meg and the reaper April, but even he knew that this kiss wasn’t great. Dean was caught by surprise, and their faces bumped together, but Castiel didn’t care. He had to show him, in any way possible. He would give up the world for Dean—has, in fact, given up the world for him—and now he knew Dean would—He _wanted_ to stop, for _Castiel_ —

“Cas,” Dean breathed against his mouth when Castiel pulled away a little. Castiel looked down, still gripping Dean’s jacket in his fists. He didn’t want to let go, but he was struck abruptly by doubt. Maybe he had made a mistake. Maybe he had misunderstood. But when he raised his gaze to see, Dean was looking at him with something like awe, though confusion creased his brow. His eyes flicked back and forth between Castiel’s, and then he leaned in again and kissed Castiel back.

This kiss was different. It alternated between cautious and fervent, and Dean had to break away occasionally to take a breath, but they clung to each other, fists in one another’s clothes, like shipwreck survivors scrabbling for purchase. There was still so much to do, still so much between them, but they weren’t letting go. They weren’t going to give up.

“Cas,” said Dean at last. “Will you… stay? Can you… Will you stay with me?”

“Of course,” said Castiel.

They didn’t have sex that night. Castiel was sure Dean would want to eventually, but Dean was too tired, and the day—the last few days, months even—had been too traumatic. There was still some uncertainty, too, a sense of distrust, though Castiel couldn’t say if the doubt was caused by what happened between them in the past, or maybe disbelief that what was happening _now_ was real. That night, Dean led Castiel to his room, and they curled protectively around each other in Dean’s bed. Castiel watched him sleep, marveled over the glow of his soul, and even then he knew he would have to make a choice.

“Castiel?”

He finally looks back up at Hannah, who watches him with a slight frown.

“Yes,” he says hoarsely. “I need your help. You have been a good friend to me, Hannah.” He produces his angel blade from the sleeve of his coat, and Hannah stiffens minutely, so Castiel hurries to explain the unexplainable. “I have no right to ask this of you. I have betrayed Heaven, over and over again, and now…” He steps toward her, and she watches him warily and then with wide-eyed surprise when he kneels before her and offers up his blade. “Now I must ask you to help me betray it one last time.”

Hannah stares at him, looking from his blade to his face. Her vessel’s dark eyes narrow.

“You would ask me to take your Grace,” she says, anger deepening the voice of her vessel. “You would ask me to aid your Fall.”

He cannot deny it. “Yes.”

“Why?”

Because Metatron was right. Because Anna had been right. Because humanity was beautiful and terrible, and their Father ordered them to love them, and so Castiel did. And it drove him to want.

“Because I want,” says Castiel. “Because I—My very existence is a blasphemy, is... is profane. I want, and I cannot continue to pretend I can keep one foot in Heaven and one on Earth without failing one of them. I cannot keep failing my family.”

“You choose Earth,” says Hannah flatly. “You choose… them. The humans.” She pauses. “No. The Winchesters.”

“Yes.”

“Why?”

“Because I want…” _Dean_. “I want to be with him,” he says quietly.

Hannah frowns. “I don’t understand. Why now? Why do you choose this now?”

“I can’t do it anymore, Hannah,” he says, his voice breaking. “I want this, and I can’t be torn in two any longer. Please… I’ve broken our laws, and I just… Please, let me go.”

Hannah doesn’t move, and Castiel bows his head, still holding up his blade in both hands. He feels Hannah’s gaze, and then her Grace, examining him, and he waits.

He feels it, the moment she realizes. Her Grace recoils, and she takes a step back. Then she stops.

When she speaks, she doesn’t sound repulsed. She sounds incredulous. “You’ve lain with him,” she says. “You’ve lain with the human Dean Winchester.”

Castiel can feel himself shaking. Shame burns hot, and he wants to not be ashamed of this. He _wants_. How can that be so terrible? How can it be sin? It is so good. He feels so full and light and _happy_. Angels aren’t supposed to feel those things, save for their Father. But how can it be wrong?

“Yes,” he says.

“Castiel,” says Hannah, her voice hushed, the anger returned. “You have broken one of our most sacred laws—”

“Which only exists to prevent the conception of a Nephilim,” he points out bitterly, “which is physically impossible between Dean and I—”

“That’s beside the point!” she hisses. “It is our law, Castiel!”

“So punish me,” he says, finally meeting her eyes again. “I have broken our laws. I have wants. Earthly desires. I am no angel. And I cannot pretend to be anymore.”

Hannah glowers at him. She is angry and disappointed, and Castiel understands why, and he feels shame but not guilt. Not regret.

She finally reaches for his blade, and he drops his hands and bows his head once more, to await judgement. It seems like a long time before Hannah places the tip of his blade under his chin, but she only tips his head up to look him in the eye. She examines him for an eon longer.

And then she says, “I will help you do this thing.”

 

* * *

 

 

When it’s over and Hannah helps him to his feet and presses her palm to his throat to heal his vessel—his body now, now it’s just his body—Sam opens the door to the bunker to begin his morning run. He stops short when he sees them, eyes wide, and then he scowls and takes several long, predatory steps toward them.

“Hey!” he shouts, and he looks ready to break into a run and attack, but Castiel stops him.

“It’s okay,” he says, but his voice only comes out in a hoarse whisper. “It’s Hannah.”

Luckily, Sam hears him. He stops. “Hannah?”

“Hello, Sam Winchester,” says Hannah, tipping her head in a small bow.

“What are you—Cas, what’s going on?”

But Castiel cannot answer. His throat closes up against a wave of sensation, and he shuts his eyes. He’d forgotten how strange humanity felt. How silent it is. How lonely.

“Whoa, whoa,” says Sam, and Castiel opens his eyes and finds that his knees have buckled, and Sam has rushed forward to duck under Castiel’s arm to support him. “All right, we gotcha, Cas. Let’s get you inside.”

Sam and Hannah carry him into the bunker and down the stairs, and they sit him down in one of the chairs at the war room table. He sighs and collapses back into it, closing his eyes again.

“Cas, what happened?” asks Sam. “Why were you outside? Why is Hannah here?”

Castiel takes a deep breath. “I—”

“Cas?” Dean’s voice echoes down the hall from the direction of the sleeping quarters. Castiel opens his eyes and turns just in time to see Dean emerging into the war room from the dark hall. Castiel’s stomach drops, which is a strange sensation all on its own _without_ the dread that accompanies it. That’s right. He can’t see Dean’s soul anymore. Not like he could as an angel.

“Dean,” he croaks. Dean’s eyes widen, and he takes an aborted step into the room, his eyes flicking to Hannah.

“Who—” Dean begins.

“It’s Hannah,” says Sam. “I found them outside.”

It’s harder to tell without the colors of Dean’s soul indicating his feelings, but Castiel knows that expression: suspicion and concern. Fear.

“What are you doing here?” Dean demands of Hannah. “I thought Heaven basically told Cas to go fuck himself. What do you want?”

“Dean,” Castiel tries again.

Hannah frowns. “I came here at Castiel’s request.”

“ _What?_ ”

“ _Dean_ ,” Castiel says again, louder, and Dean turns to him at last. He reaches out, and Dean finally strides over to him, casting a suspicious glare at Hannah. Castiel tugs at him until he gets the hint and kneels next to Castiel’s chair so he can place a hand on either side of Dean’s face and look right into his eyes.

“Oh,” he breathes out, relieved. “Good.”

Dean rests his hands on Castiel’s wrists. “Cas, what’s going on?”

Castiel runs his thumbs over Dean’s cheekbones, still staring into his eyes. It’s not the same, but it’s okay. The light is still there; he can see it.

It’s the one thing he knew he would miss the most. And it’s okay.

“Cas?”

Castiel finally looks down. That’s right. He has to admit to Dean what he’s done. Suddenly, the uncertainty is overwhelming. Anxiety boils his insides, pushes bile into his throat. He’s useless, now, without his Grace. Dull and broken; a baby in a trench coat. Will Dean hate it? Will he leave Castiel because of it? This is what Castiel wanted—to be human, to experience the world in the pure way that humans do, in all its complexities and wonder, to love Dean the way Castiel wants to, to have the freedom to _want_ —but he had forgotten to think of Dean’s reaction.

Last time, he had told him to leave.

“Cas,” says Dean, a little more impatiently.

“I asked Hannah to come here,” he says at last, swallowing against the pain in his sore throat, “to take my Grace.”

Dean’s gaze snaps to Hannah. “What?” He turns back to Castiel just as quickly. “Why?”

“I want to stay here,” says Castiel quietly. It’s easier to whisper. “With you.”

“Of course you can stay,” says Dean, panic leaking into his tone. Oh, good. He can stay. He can stay. “But you can—you can do that with your Grace, man. You don’t gotta—That’s a part of you, you don’t have to give it up.”

“I can’t be an angel,” says Castiel slowly, because that’s easier, too, and he wants Dean to understand, “and be with you. I _want_ to…”

“God damn it, Cas,” Dean growls, and then he stands up, breaking their contact, and it’s so lonely. He’d forgotten. But it’s okay. He wants this. He’s been considering it for a long time now. It’s okay. He’ll adjust. It’ll be worth it.

He gets to stay. It’ll be worth it.

“Why the hell would you agree to this?” Dean spits at Hannah, rounding on her. “He’s your brother. Why would you—”

“He asked me to,” says Hannah, simply, raising her chin, and Castiel feels a wave of affection for her. He’ll miss her. Maybe he’ll pray to her. “And he’s broken a sacred law,” she adds.

“What law?” Dean demands, indignant and incredulous.

“Angels are forbidden to lie with humans,” says Hannah, and Dean stiffens. “Castiel has lain with you. I had to… punish him.” She glances at Castiel.

_I remember what it was like_ , she had said, outside of the bunker. _I respect your choice. So though it gives me no pleasure, I will help you do this thing._

The other angels wouldn’t understand, still don’t, even after the Fall. It’s not a punishment; never could be. But if saying it is would satisfy the others in Heaven, then that’s what they would call it.

Dean stares at her, and suddenly, Sam chokes out a laugh.

“Wait,” he says, his face twitching from suppressed amusement. “You’ve… _lain_ together?” he asks, raising his eyebrows and pressing his lips together.

Dean closes his eyes. “Sam…”

Sam snickers.

Hannah ignores them and turns to Castiel. “I must return to Heaven,” she says, and Castiel nods. She looks down then, and the fist curled around the vial containing his Grace tightens. “Are you certain…?”

“It’s yours now,” he says. “Do with it as you see fit.”

She hesitates, then nods. Then she steps forward and slowly places his blade on the table next to him. “This is still yours,” she tells him. “It will always be yours.”

“Thank you,” he manages.

Hannah nods again. She glances at the Winchesters, who are now watching them both warily, and then moves to stand before Castiel. Dean clenches his fists and shifts, but Hannah only leans down to place a kiss on Castiel’s forehead.

“Good-bye, Castiel,” says Hannah. It’s redundant; they’ve already said good-bye. In the moments before she cut his Grace out of him, their true forms shared one last embrace. But somehow this good-bye feels significant anyway.

“Thank you, Hannah,” Castiel whispers.

She smiles at him and turns to leave, but before she reaches the stairs to the bunker door, she stops.

“Dean Winchester,” says Hannah, and Dean starts, straightening. Hannah glances at Castiel once more before turning her gaze on Dean. After a long pause, she speaks again. “Take care of my brother.”

Dean blinks, taken aback. “Uh,” he says. “Yeah. I—Okay.”

Hannah stares at him a moment longer in disbelief, and Castiel looks down to hide a smile. When he looks back up, Hannah gives Castiel a skeptical frown. He just shrugs. Shaking her head, Hannah mounts the stairs and goes out into the bright morning.

The bunker is silent for a few moments. Sam breaks it by snickering again.

“Sam,” Dean warns.

“So, uh, how long has this been going on?” asks Sam, grinning.

Dean turns to glare at him, fists clenched, his face and neck red. Sam raises his eyebrows expectantly.

“Later,” Dean mutters at last, and Sam nods and claps a hand on Dean’s shoulder.

“Well, congratulations, you two,” says Sam, still grinning. “It’s about damn time.”

“Shut up,” Dean grumbles, smacking Sam’s arm away. He glances at Castiel and scratches the back of his head. “You okay?”

Castiel nods. “Just… tired.”

“So,” says Dean, shifting, his hands opening and closing, “so, you… you’re human now? Again?”

He nods again and looks down at his hands. All of the sensations are closer now, unfiltered by his Grace. He’s lost the senses that his Grace afforded him and gained an exponential increase in others. He’ll be able to taste peanut butter and jelly sandwiches again. He can feel the ridges in his fingerprints and they aren’t just stacked cells now; they’re patterns, unique and his alone. There are fewer colors, but he appreciates how the ones he can see are arranged—the pink and light tan on his hands, the deep blue of his pants. He remembers that flowers looked different with the limits of human eyes and thinks he’d like to see that again. This is how humans see the world. With all its flaws, it’s still beautiful.

“How does it feel?” asks Sam.

“There’s… a lot,” he admits. “But I remember… I’ll adjust.”

“Do you… What do you need?” asks Dean. “Are you hungry? Do you need water? Sleep?”

Castiel reaches for him again, and this time Dean kneels without prompting.

“What is it, buddy?” Dean whispers. “What do you need?”

Castiel draws him into an embrace and tucks his face into Dean’s neck. Dean holds him, and Castiel takes a deep breath.

“You,” says Castiel.

**Author's Note:**

> I’m debating on whether or not to write the direct aftermath of this. I feel like it might be too self-indulgent... But would anyone be interested in reading about Cas’s first birthday party? :D
> 
> Also? I highly recommend listening to this song. It’s beautiful.


End file.
